The Immune System: non specific defences Flashcards
define Non specific immunity
Mechanisms that protect the body against a wide range of dangers
Usually present from birth, innate
define Specific immunity
Mechanisms directed specifically against one invader
Body adapts to learning and remembering specific antigens to build an immunological memory
define Immunity
Specific defence mechanisms
define Antigen
Anything that stimulates an immune response
What are the 5 main non specific defences
Epithelial barriers
Phagocytosis
Natural anti microbial substances
The inflammatory response
Immunological surveillance
What is the function of the non specific defences
First line of defence to prevent entry of microbes and other foreign material
what are the Epithelial barriers
Skin and mucous membranes, nose hair, cilia
describe how nose hair acts as an epithelial barrier
Filter system to stop larger foreign bodies being inhaled and entering respiratory tract
describe how cilia acts as an epithelial barrier
Waft mucus and inhaled foreign materials towards the throat so it’s is coughed up or swallowed
what are epithelial secretions
E.g. oral,vaginal, gastric
Are antibacterial and often acidic, containing antibodies and enzymes
Describe examples of epithelial secretions
Sebum and sweat contain antibacterial and anti fungal properties
what are Anti microbial substances
Saliva, lysozyme, Hydrochloric acid (present in gastric acid), antibodies, interferons
describe how saliva acts as an antimicrobial substance
Washes away food debris to prevent bacterial growth
Contains antibodies, lysozyme and buffers to neutralise bacterial acids that promote dental decay
describe how a Lysozyme acts as an antimicrobial substance
Antibacterial enzyme present in tears
describe how a Antibodies acts as an antimicrobial substance
Protective proteins inactivate bacteria
Coat membranes exposed to the external environment
describe Phagocytosis
Neutrophils and macrophages
Move to sites of inflammation and infection as they are attracted to chemicals released by invaders
Attack, digest, destroy
Release toxic chemical
Chemicals released alert immune system
Characteristics of neutrophils
Short lived, destroy themselves with their toxic chemicals
Characteristics Macrophages
Live longer and link the non-specific defences with specific immunity
define the Inflammatory response
Physiological response to tissue damage
Describe inflammatory response, increased blood flow
Arterioles and capillaries dilate
So more oxygen provided to area
Increases temperature to specific area
Swelling and redness and temperature caused by local release of histamine and serotonin
Inflammatory response accumulation of tissue fluid
More blood flowing means more water/fluid leaking out of blood vessels
Histamines and serotonin make capillaries’ walls more permeable
Inflammatory response, migration of leukocytes
Blood left in blood vessels are thicker from loss of fluid/water, so flow is slower allowing white blood cells to attach to vessel wall to enter the tissues
inflammatory response, increased core temperature
inhibits growth and division of microbes while promoting phagocytosis
inflammatory response, pain
encourages protection, local swelling compresses sensory nerve endings
